Intel has showed a prototype smartphone based on its low-power Medfield processor and said Intel-based phones from "major players" would be in the market next year. Intel has struggled to get its chips into smartphones and tablets, markets that are dominated today by processor designs from Intel's U.K. rival ARM Holdings.

I think the terrible performance of modern desktop OSs mostly has to do with a bad sense of priorities...
-Do you need your operating system to initialize the network stack before displaying the login screen if you log in locally ?
-Do you need your operating system to initialize all peripherals including things like webcams, scanners, printers or USB sticks before displaying that login screen, or do you only want main graphics output and input devices like the mouse and the keyboard to be initialized now, and the rest to be initialized in the background later ?
-When you're encoding an HD movie in the background and browsing your HDD hierarchy in the foreground, which task should receive the highest HDD access priority and provide maximal reactivity ?

Then there are also more classical ways to waste CPU power. Like, you know, this habit of many graphical toolkits to fully redraw a window each time it's moved a few pixels around, instead of just keeping a copy of its contents in a buffer and blitting that copy around.